Improve German date format parser

This allow to parse German dates without leading zeros, e.g. 1.1.2015 instead of 01.01.2015

Author: kakra

lib/chronic/parser.rb

@@ -94,7 +94,7 @@ def parse(text)
     # Returns a new String ready for Chronic to parse.
     def pre_normalize(text)
       text = text.to_s.downcase
-      text.gsub!(/\b(\d{2})\.(\d{2})\.(\d{4})\b/, '\3 / \2 / \1')
+      text.gsub!(/\b(\d{1,2})\.(\d{1,2})\.(\d{4})\b/, '\3 / \2 / \1')
       text.gsub!(/\b([ap])\.m\.?/, '\1m')
       text.gsub!(/(\s+|:\d{2}|:\d{2}\.\d+)\-(\d{2}:?\d{2})\b/, '\1tzminus\2')
       text.gsub!(/\./, ':')